378 Dr. M' Sweeny on the Ventilation of Mines. [Nov. 



would be a matter of some importance. It may be thus accom- 

 plished. The main tube coming from the valve of the bellows 

 should divide into a number of branches, each branch near its 

 commencement being furnished with a cock. We shall sup- 

 pose that the tube coming from the bellows divides into three 

 branches, and for the sake of perspicuity shall call what conveys 

 off the gas, tube, and what conveys up the water, pipe. If 

 there be an air-tight box, or cistern, placed about 30 feet above 

 . the level of the water in the mine furnished with a pipe descend- 

 ing from its bottom into the water below, it is evident that if 

 we exhaust the air out of this cistern, the water will ascend up 

 the pipe, and will fill the cistern, and may be prevented from 

 returning by valves placed in the pipe. By this plan we get the 

 water up one lift. Now to get it up a second, the cistern should 

 be provided with a valve on its top, opening upwards. When 

 this valve is pulled up, the atmospheric pressure on the surface 

 of the water in the cistern will force it up a second similar pipe 

 (which rises through the water from near its bottom) to a second 

 similar cistern placed about 30 feet above the bottom of the first 

 one, provided an exhaustion is taking place in this second 

 cistern. By this process the water may be raised from the 

 second cistern to a third, and from a third to a fourth, and so 

 on to any height. 



The means of exhausting the cisterns of air now remains to be 

 explained. We suppose the large bellows to be at work, and 

 that the cocks of all the branches of the main tube coming from 

 the valve of the bellows are shut, except the cock of the first 

 branch. The first branch descends down to the top of the first 

 cistern ; the exhaustion, by means of the bellows, takes place 

 through this branch, consequently the water rises to fill the first 

 cistern. When this cistern is full, the cock of the first branch 

 is shut, and that of the second branch (which descends down to 

 the top of the second cistern) is opened; of course an exhaustion 

 takes place, and the water rises from the first to fill the second 

 cistern, the valve on the top of the first cistern being pulled up 

 to allow of the atmospheric pressure. When the cock of the 

 second branch is shut, and that of the third opened, the water 

 can be made to rise from the second cistern in like manner to 

 fill a third one above it, and so on. Water raised from a mine, 

 or any other water, provided there be some fall, may be employed 

 for freeing a mine from gas by the following contrivance : Let 

 II (PI. CIX) fig. 13, be a pipe coming from a reservoir of water, 

 and F a tube going down to the bottom of a mine. When the 

 cock y is turned, the water flows into the long air-tight cistern 

 A, and drives the air out, which escapes through the valve v, 

 not being able to escape through the tube F, on account of the 

 valve 71. When the cistern A is full of water, y is to be shut, 

 and the cock g is to be opened ; the water now flows into the 

 cistern B, and A becomes full of gas from the mine through the 



